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<br> <P align=center class=MsoNormal style="TEXT-ALIGN: center"><B style="mso-bidi-font-weight: normal"><SPAN style="FONT-FAMILY: 宋体; FONT-SIZE: 16pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">在</SPAN></B><B style="mso-bidi-font-weight: normal"><SPAN lang=EN-US style="FONT-SIZE: 16pt">Java</SPAN></B><B style="mso-bidi-font-weight: normal"><SPAN style="FONT-FAMILY: 宋体; FONT-SIZE: 16pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">中实现回调过程</SPAN></B><B style="mso-bidi-font-weight: normal"><SPAN lang=EN-US style="FONT-SIZE: 16pt"><?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><o:p></o:p></SPAN></B></P> <P align=right class=MsoNormal style="TEXT-ALIGN: right"><B style="mso-bidi-font-weight: normal"><SPAN style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">在</SPAN><SPAN lang=EN-US>Java</SPAN></B><B style="mso-bidi-font-weight: normal"><SPAN style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">使用接口来实现同样功能的回调函数</SPAN><SPAN lang=EN-US><o:p></o:p></SPAN></B></P> <P class=MsoNormal><SPAN lang=EN-US><o:p> </o:p></SPAN></P> <P class=MsoNormal><B style="mso-bidi-font-weight: normal"><SPAN style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">摘要</SPAN><SPAN lang=EN-US>:<o:p></o:p></SPAN></B></P> <P class=MsoNormal style="TEXT-INDENT: 21pt"><SPAN lang=EN-US>Java</SPAN><SPAN style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">接口提供了一个很好的方法来实现回调函数。如果你习惯于在事件驱动的编程模型中，通过传递函数指针来调用方法达到目的的话，那么你就会喜欢这个技巧。</SPAN></P> <P class=MsoNormal><SPAN lang=EN-US><o:p> </o:p></SPAN></P> <P class=MsoNormal><B style="mso-bidi-font-weight: normal"><SPAN style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">作者：</SPAN><SPAN lang=EN-US>John D. Mitchell<o:p></o:p></SPAN></B></P> <P class=MsoNormal><SPAN lang=EN-US><o:p> </o:p></SPAN></P> <P class=MsoNormal style="TEXT-INDENT: 21pt"><SPAN style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">在</SPAN><SPAN lang=EN-US>MS-Windows</SPAN><SPAN style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">或者</SPAN><SPAN lang=EN-US>X-Window</SPAN><SPAN style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">系统的事件驱动模型中，当某些事件发生的时候，开发人员已经熟悉通过传递函数指针来调用处理方法。而在</SPAN><SPAN lang=EN-US>Java</SPAN><SPAN style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">的面向对象的模型中，不能支持这种方法，因而看起来好像排除了使用这种比较舒服的机制，但事实并非如此。</SPAN></P> <P class=MsoNormal style="TEXT-INDENT: 21pt"><SPAN lang=EN-US>Java</SPAN><SPAN style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">的接口提供了一种很好的机制来让我们达到和回调相同的效果。这个诀窍就在于定一个简单的接口，在接口之中定义一个我们希望调用的方法。</SPAN></P> <P class=MsoNormal style="TEXT-INDENT: 21pt"><SPAN style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">举个例子来说，假设当一个事件发生的时候，我们想它被通知，那么我们定义一个接口：</SPAN></P> <TABLE border=1 cellPadding=0 cellSpacing=0 class=MsoNormalTable style="BACKGROUND: #cccccc; WIDTH: 100%; mso-cellspacing: 0cm; mso-padding-alt: 3.75pt 3.75pt 3.75pt 3.75pt" width="100%"> <TBODY> <TR style="mso-yfti-irow: 0; mso-yfti-lastrow: yes"> <TD style="PADDING-BOTTOM: 3.75pt; PADDING-LEFT: 3.75pt; PADDING-RIGHT: 3.75pt; PADDING-TOP: 3.75pt"> <P align=left class=MsoNormal style="TEXT-ALIGN: left; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt">public interface InterestingEvent<o:p></o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt">{<o:p></o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt"><SPAN style="mso-spacerun: yes"> </SPAN>// This is just a regular method so it can return something or<o:p></o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt"><SPAN style="mso-spacerun: yes"> </SPAN>// take arguments if you like.<o:p></o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt"><SPAN style="mso-spacerun: yes"> </SPAN>public void interestingEvent ();<o:p></o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt">}<o:p></o:p></SPAN></P></TD></TR></TBODY></TABLE> <P class=MsoNormal style="TEXT-INDENT: 21pt"><SPAN style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">这就给我们一个控制实现了该接口的所有类的对象的控制点。因此，我们不需要关心任何和自己相关的其它外界的类型信息。这种方法比</SPAN><SPAN lang=EN-US>C</SPAN><SPAN style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">函数更好，因为在</SPAN><SPAN lang=EN-US>C++</SPAN><SPAN style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">风格的代码中，需要指定一个数据域来保存对象指针，而</SPAN><SPAN lang=EN-US>Java</SPAN><SPAN style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">中这种实现并不需要。</SPAN></P> <P class=MsoNormal style="TEXT-INDENT: 21pt"><SPAN style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">发出事件的类需要对象实现</SPAN><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt">InterestingEvent接口，然后调用接口中的interestingEvent ()方法。</SPAN></P> <TABLE border=1 cellPadding=0 cellSpacing=0 class=MsoNormalTable style="BACKGROUND: #cccccc; WIDTH: 100%; mso-cellspacing: 0cm; mso-padding-alt: 3.75pt 3.75pt 3.75pt 3.75pt" width="100%"> <TBODY> <TR style="mso-yfti-irow: 0; mso-yfti-lastrow: yes"> <TD style="PADDING-BOTTOM: 3.75pt; PADDING-LEFT: 3.75pt; PADDING-RIGHT: 3.75pt; PADDING-TOP: 3.75pt"> <P align=left class=MsoNormal style="TEXT-ALIGN: left; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt">public class EventNotifier<o:p></o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt">{<o:p></o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt"><SPAN style="mso-spacerun: yes"> </SPAN>private InterestingEvent ie;<o:p></o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; TEXT-INDENT: 24pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt">private boolean somethingHappened; <o:p></o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; TEXT-INDENT: 24pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt"><o:p> </o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt"><SPAN style="mso-spacerun: yes"> </SPAN>public EventNotifier (InterestingEvent event)<o:p></o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; TEXT-INDENT: 24pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt; mso-char-indent-count: 2.0"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt">{<o:p></o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; TEXT-INDENT: 36pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt; mso-char-indent-count: 3.0"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt">// Save the event object for later use.<o:p></o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; TEXT-INDENT: 36pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt; mso-char-indent-count: 3.0"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt">ie = event; <o:p></o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; TEXT-INDENT: 36pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt; mso-char-indent-count: 3.0"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt">// Nothing to report yet.<o:p></o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; TEXT-INDENT: 36pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt; mso-char-indent-count: 3.0"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt">somethingHappened = false;<o:p></o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; TEXT-INDENT: 24pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt; mso-char-indent-count: 2.0"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt">} <o:p></o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt"><SPAN style="mso-spacerun: yes"> </SPAN>//...<SPAN style="mso-spacerun: yes"> </SPAN><o:p></o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt"><SPAN style="mso-spacerun: yes"> </SPAN>public void doWork ()<o:p></o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt"><o:p> </o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt"><o:p> </o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; TEXT-INDENT: 24pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt; mso-char-indent-count: 2.0"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt">{<o:p></o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; TEXT-INDENT: 48pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt; mso-char-indent-count: 4.0"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt">// Check the predicate, which is set elsewhere.<o:p></o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; TEXT-INDENT: 48pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt; mso-char-indent-count: 4.0"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt">if (somethingHappened)<o:p></o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; TEXT-INDENT: 24pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt; mso-char-indent-count: 2.0"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt"><SPAN style="mso-spacerun: yes"> </SPAN>{<o:p></o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; TEXT-INDENT: 48pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt; mso-char-indent-count: 4.0"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt"><SPAN style="mso-spacerun: yes"> </SPAN>// Signal the even by invoking the interface's method.<o:p></o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; TEXT-INDENT: 48pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt; mso-char-indent-count: 4.0"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt"><SPAN style="mso-spacerun: yes"> </SPAN>ie.interestingEvent ();<o:p></o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; TEXT-INDENT: 36pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt; mso-char-indent-count: 3.0"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt"><SPAN style="mso-spacerun: yes"> </SPAN>}<o:p></o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; TEXT-INDENT: 48pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt; mso-char-indent-count: 4.0"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt">//...<o:p></o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt"><SPAN style="mso-spacerun: yes"> </SPAN>} <o:p></o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt"><SPAN style="mso-spacerun: yes"> </SPAN>// ...<o:p></o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt">}<o:p></o:p></SPAN></P></TD></TR></TBODY></TABLE> <P class=MsoNormal style="TEXT-INDENT: 21pt"><SPAN style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">在这个例子中，我们使用了</SPAN><SPAN lang=EN-US>somethingHappened</SPAN><SPAN style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">这个标志来跟踪是否事件应该被激发。在许多事例中，被调用的方法能够激发</SPAN><SPAN lang=EN-US>interestingEvent()</SPAN><SPAN style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">方法才是正确的。</SPAN><SPAN lang=EN-US><o:p></o:p></SPAN></P> <P class=MsoNormal style="TEXT-INDENT: 21pt"><SPAN style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">希望收到事件通知的代码必须实现</SPAN><SPAN lang=EN-US>InterestingEvent</SPAN><SPAN style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">接口，并且正确的传递自身的引用到事件通知器。</SPAN></P> <TABLE border=1 cellPadding=0 cellSpacing=0 class=MsoNormalTable style="BACKGROUND: #cccccc; WIDTH: 100%; mso-cellspacing: 0cm; mso-padding-alt: 3.75pt 3.75pt 3.75pt 3.75pt" width="100%"> <TBODY> <TR style="mso-yfti-irow: 0; mso-yfti-lastrow: yes"> <TD style="PADDING-BOTTOM: 3.75pt; PADDING-LEFT: 3.75pt; PADDING-RIGHT: 3.75pt; PADDING-TOP: 3.75pt"> <P align=left class=MsoNormal style="TEXT-ALIGN: left; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt">public class CallMe implements InterestingEvent<o:p></o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt">{<o:p></o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; TEXT-INDENT: 24pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt">private EventNotifier en; <o:p></o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; TEXT-INDENT: 24pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt"><o:p> </o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt"><SPAN style="mso-spacerun: yes"> </SPAN>public CallMe ()<o:p></o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; TEXT-INDENT: 24pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt; mso-char-indent-count: 2.0"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt">{<o:p></o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; TEXT-INDENT: 36pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt; mso-char-indent-count: 3.0"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt">// Create the event notifier and pass ourself to it.<o:p></o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; TEXT-INDENT: 36pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt; mso-char-indent-count: 3.0"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt">en = new EventNotifier (this);<o:p></o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; TEXT-INDENT: 24pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt; mso-char-indent-count: 2.0"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt">} <o:p></o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt"><o:p> </o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt"><SPAN style="mso-spacerun: yes"> </SPAN>// Define the actual handler for the event.<o:p></o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt"><SPAN style="mso-spacerun: yes"> </SPAN>public void interestingEvent ()<o:p></o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; TEXT-INDENT: 24pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt; mso-char-indent-count: 2.0"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt">{<o:p></o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; TEXT-INDENT: 36pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt; mso-char-indent-count: 3.0"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt">// Wow!<SPAN style="mso-spacerun: yes"> </SPAN>Something really interesting must have occurred!<o:p></o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; TEXT-INDENT: 36pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt; mso-char-indent-count: 3.0"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt">// Do something...<o:p></o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; TEXT-INDENT: 36pt; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt; mso-char-indent-count: 3.0"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt">} <o:p></o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt"><SPAN style="mso-spacerun: yes"> </SPAN>//...<o:p></o:p></SPAN></P> <P align=left class=MsoNormal style="TEXT-ALIGN: left; mso-pagination: widow-orphan; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><SPAN lang=EN-US style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt">}<o:p></o:p></SPAN></P></TD></TR></TBODY></TABLE> <P class=MsoNormal><SPAN style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">希望这点小技巧能给你带来方便。</SPAN></P> <P class=MsoNormal><SPAN lang=EN-US><o:p> </o:p></SPAN></P> <P class=MsoNormal><B style="mso-bidi-font-weight: normal"><SPAN style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">关于作者：</SPAN><SPAN lang=EN-US><o:p></o:p></SPAN></B></P> <P class=MsoNormal><SPAN lang=EN-US>John D. Mitchell</SPAN><SPAN style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">在过去的九年内一直做顾问，曾经在</SPAN><SPAN lang=EN-US style="FONT-FAMILY: Verdana">Geoworks</SPAN><SPAN style="FONT-FAMILY: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana">使用</SPAN><SPAN lang=EN-US style="FONT-FAMILY: Verdana">OO</SPAN><SPAN style="FONT-FAMILY: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana">汇编语言</SPAN><SPAN style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">开发了</SPAN><SPAN lang=EN-US>PDA</SPAN><SPAN style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">软件，兴趣于写编译器，</SPAN><SPAN lang=EN-US>Tcl/Tk</SPAN><SPAN style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">和</SPAN><SPAN lang=EN-US>Java</SPAN><SPAN style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">系统。和人合著了《</SPAN><SPAN lang=EN-US>Making Sense of Java</SPAN><SPAN style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">》，目前从事</SPAN><SPAN lang=EN-US>Java</SPAN><SPAN style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">编译器的工作。</SPAN><SPAN lang=EN-US><o:p></o:p></SPAN></P><br>
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